Open mold wide profile carbon wheels

Everything about building wheels, glueing tubs, etc.
tomycs
Posts: 55
Joined: Tue Mar 15, 2016 1:06 pm

by tomycs

I'm assuming rim brake. I've only had experiences with 2 manufacturers: the x degrees angled brake track of Farsports (decent in dry but typical carbon in wet, works well with most pads, slightly better with Campagnolo reds and Giant greys) and venn (pulsing with any sort of decent braking pad). They are also quite different in width though 23mm/C17-Farsports and 28mm/C21-venn. In my experience and the terrain I'm covering (no climbs longer than 2km) the Farsports compares well in the dry with older Enve and older Campagnolo braking. I would not take them to the Alps though.

Svetty
Posts: 513
Joined: Thu Mar 26, 2009 11:06 pm
Location: Yorkshire - God's Own Country

by Svetty

Just built up a set of LB rim braked wheels. I've never used carbon rim brakes before. In the dry they brake as well as alloy rims. I've not ridden them in the wet yet.....

by Weenie


belopsky
Posts: 4
Joined: Fri May 25, 2018 12:13 pm

by belopsky

I stumbled on this thread after looking at a Wraith Hustle build thread. I just got a Wraith that is built up to 18.2lbs with some HUNT alloy wheels.

https://www.aliexpress.com/item/Farspor ... 06624.html
^How are these? With Bitex hubs they're $550 :D

Should I spend a tad more and get the Light Bicycle?
I was looking at these. $6xx USD shipped for the same hubs

I worry about braking because it gets wet here, but when it is wet I generally ride my other bikes..

Hexsense
Posts: 524
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

belopsky wrote:
Fri May 25, 2018 12:15 pm
I stumbled on this thread after looking at a Wraith Hustle build thread. I just got a Wraith that is built up to 18.2lbs with some HUNT alloy wheels.

https://www.aliexpress.com/item/Farspor ... 06624.html
^How are these? With Bitex hubs they're $550 :D

Should I spend a tad more and get the Light Bicycle?
Absolutely, unless you use 21c tire.
Didn't you see that the rim is only 23mm wide externally?
23c clincher is 25-27mm wide depend on the combo. Get a rim that is at least nearly as wide as your tire, or better, wider than the tire for good aerodynamic.

Those 23mm external width can sell well because people only look at depth and weight. But forget about why they want deep wheel in the first place (for aero) and how rim way narrower than your tire is not aero.

belopsky
Posts: 4
Joined: Fri May 25, 2018 12:13 pm

by belopsky

Hexsense wrote:
Fri May 25, 2018 4:16 pm
belopsky wrote:
Fri May 25, 2018 12:15 pm
I stumbled on this thread after looking at a Wraith Hustle build thread. I just got a Wraith that is built up to 18.2lbs with some HUNT alloy wheels.

https://www.aliexpress.com/item/Farspor ... 06624.html
^How are these? With Bitex hubs they're $550 :D

Should I spend a tad more and get the Light Bicycle?
Absolutely, unless you use 21c tire.
Didn't you see that the rim is only 23mm wide externally?
23c clincher is 25-27mm wide depend on the combo. Get a rim that is at least nearly as wide as your tire, or better, wider than the tire for good aerodynamic.

Those 23mm external width can sell well because people only look at depth and weight. But forget about why they want deep wheel in the first place (for aero) and how rim way narrower than your tire is not aero.
I have 28mm tires now, what width do I want?

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Beaver
Posts: 501
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

You could buy Light Bicycle rims with 21mm inside width and run 25mm tires with the same pressure you use with your 28mm tires now. Comfort will be the same but rolling resistence is lower and aerodynamics will be better. But we are talking about low one digit watt differences at 45km/h, where 450 watts are needed overall. What you will notice is a better crosswind stability with a rim that is as wide as your tire or even wider (105 to 110% of the tire).

A 28mm tire on a 17C/23mm wide rim does everything worse.

belopsky
Posts: 4
Joined: Fri May 25, 2018 12:13 pm

by belopsky

The issue is that our roads are bad, I don't want to ride anything smaller than 28mm tire

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Beaver
Posts: 501
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

Comfort is mainly dictated by tire pressure - the tire flanges will stand straighter on a wider rim and stabilize the whole system. You can really run pressures as low as on a 28mm tire with a 25mm tire on a 21C rim (it will also become more than 28mm wide). 5 bar will be enough, even for heavier riders. If you really want to stick with 28mm you could wait for the new 23C Light Bicycle rim. But a Conti 4000S II will be 33mm wide on these, I don't know what frame you ride and if it would fit. But you could run a really low pressure on these...

Hexsense
Posts: 524
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

belopsky wrote:
Fri May 25, 2018 10:04 pm
The issue is that our roads are bad, I don't want to ride anything smaller than 28mm tire
25c on rim that wide is already more than 28mm wide. So you could run 25c the same pressure as your current 28c too.
Even my 23c is 27.3mm on my rims.

I'd compromize, use 25c in the front (~28mm actual width) and 28c in the rear (32mm+ for conti 4000sII, 30.5mm for Vittoria Corsa G+ 28c).

Or if you want 28c front and rear, do it. At least 28c on these rim is not nearly as bad as 28c on narrow 23mm rim.

pushstart
Posts: 461
Joined: Sat Jun 16, 2012 3:12 am

by pushstart

belopsky wrote:The issue is that our roads are bad, I don't want to ride anything smaller than 28mm tire
Certainly nothing bad will happen if you run 28mm. If you're looking for that small aero gain, I am sure that there is benefit to riding a narrower tire, but I run 28mm tires on my LB 21C rims and they are wonderful.

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Beaver
Posts: 501
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

pushstart wrote:
Sat May 26, 2018 1:11 am
belopsky wrote:The issue is that our roads are bad, I don't want to ride anything smaller than 28mm tire
Certainly nothing bad will happen if you run 28mm. If you're looking for that small aero gain, I am sure that there is benefit to riding a narrower tire, but I run 28mm tires on my LB 21C rims and they are wonderful.
Nothing bad will happen, but you will loose the aero benefit of your wheels, even when the tire is only some millimeters wider than the rim. But it's just a few watts at 45km/h when 450 watts are needed overall. You might notice the lower crosswind stability though.

pushstart
Posts: 461
Joined: Sat Jun 16, 2012 3:12 am

by pushstart

Yeah, I don't disagree. I just don't think the aero difference in this case is something someone can actually perceive. Whereas the difference in comfort etc. will be very obvious with 28mm vs. 25mm.

I don't have any issues with crosswind stability with the 46mm rims -- but at around 80kg I am also not a light rider. These work very well, though, from what I can tell.

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Beaver
Posts: 501
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

The round V-Shape of the Light Bicycle rims is better in crosswinds than the torodial shapes - even with an overlapping tire. ;) Nothing comes close to the teardrop shape though. Rim height doesn't seem to matter at all here. :shock:

But the tiny aero benefits of high rims in high yaw angles are really gone if the rim width is not at least 105% of the tire. The airflow will seperate directly at the tire and the higher the rim, the more turbulences you will get. People just don't notice it, because the differences are so small. ;)

And what I didn't emphasize before, this is only valid for the front wheel. :smartass: I would only replace my 21C 28mm wide front rim with a 21C 30mm wide rim. In the back the seattube "protects" the tire leading side and at the far end, a tire that is a little wider than the rim will help to keep the airflow attached to the wheel. That's why we see 23mm front/25mm rear even on aero bikes, it just doesn't affect aerodynamics negativly.

On the rear wheel a torodial rim with 105% width of the tire will even perform worse than V-shape with a slightly overlapping tire. ;)

LD001
Posts: 89
Joined: Mon May 12, 2008 9:03 pm
Location: The Netherlands

by LD001

I have a set LB wheelset with the 46mm high 21mm internal width (hooked version). I run them with Specialized S works Turbo 26mm tires. Specialized specifies minimal 7 bar in the tires. Seems a lot to me. Any thoughts here: could I run lower pressures?

Hexsense
Posts: 524
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

Beaver wrote:
Sun May 27, 2018 10:11 am
The round V-Shape of the Light Bicycle rims is better in crosswinds than the torodial shapes - even with an overlapping tire. ;) Nothing comes close to the teardrop shape though. Rim height doesn't seem to matter at all here. :shock:

But the tiny aero benefits of high rims in high yaw angles are really gone if the rim width is not at least 105% of the tire. The airflow will seperate directly at the tire and the higher the rim, the more turbulences you will get. People just don't notice it, because the differences are so small. ;)

And what I didn't emphasize before, this is only valid for the front wheel. :smartass: I would only replace my 21C 28mm wide front rim with a 21C 30mm wide rim. In the back the seattube "protects" the tire leading side and at the far end, a tire that is a little wider than the rim will help to keep the airflow attached to the wheel. That's why we see 23mm front/25mm rear even on aero bikes, it just doesn't affect aerodynamics negativly.

On the rear wheel a torodial rim with 105% width of the tire will even perform worse than V-shape with a slightly overlapping tire. ;)
While we still agree with information we observed from other people's tests.
Each time you state the observed speculation, you sound more and more generalized and conclusive like it become indisputable fact.
I fear that this can bring us too far from what data can provide us. And something might turn out to be not completely right. Consider using Scientist's way to talk from observation: claim and generalize a bit less.


Based on what we've seen so far, there are some small details i see a bit different in your post:
1.) Aero benefit of deep wheel is not completely gone. It's just reduced. Yes, based on Specialized claims: Roval CLX32 with matching tire width is more aero than Roval CLX 40 which is too narrow for modern tire. But the CLX40 is still more aero than box section rim anyway.
2.) Tire wider than rim in the rear wheel still have negative effect to aero (it does affect aerodynamics negativly) . It's just not nearly as bad as the front. Leading edge got shielded by seat tube, tailing edge when the tire is big and end abruptly still reduce aero-ness. With combined data from Flo and Silca's tests , we do rear wider than front because rear bear more weight and load than front wheel, bigger tire in the back should save more watts through rolling resistance than it lost by a little bit of being less aero. Hence could be faster in most conditions.


LD001 wrote:
Sun May 27, 2018 9:26 pm
I have a set LB wheelset with the 46mm high 21mm internal width (hooked version). I run them with Specialized S works Turbo 26mm tires. Specialized specifies minimal 7 bar in the tires. Seems a lot to me. Any thoughts here: could I run lower pressures?
Do i have to state again that i use Continental GP Attack III, 23c at 70psi in the front with 21mm internal width rim?
Ignore the label!

by Weenie


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